Use of Vitamin C in shower filters is a relatively new concept. It is a very well-known fact that during a hot shower, the pores in our skin opens up and become highly absorbent, like a sponge. The chlorine which is added to the water to kill microbes is a very unstable while dissolved in water. Due to the heat of the shower water, the chlorine will quickly change to its gaseous state and will be released into the air. This will then mix with the confined bathroom enclosure where it is easily absorbed through the skin or inhaled into your lungs. May people with sensitive skin experience dry and itchy skin, eczema, hair loss etc. due to the exposure to chlorine in their shower water.
Vitamin C based de-chlorination
Using Vitamin C to remove chlorine from water is a relatively newer method of de-chlorination. The following USDA publication lists the advantages of using Vitamin C as a de-chlorinating agent over the other chemical methods for neutralizing chlorine.
Vitamin C Based Shower Filters
The following shower filters in the market use Vitamin C in their shower filter cartridges.
There are two types of Vitamin C used in de-chlorination. The first is Ascorbic acid and the second is Sodium Ascorbate. USDA recommends them as non-hazardous chemicals for removing chlorine from water.
Advantages of Vitamin C for Removing Chlorine
Compared to other chlorine removing chemicals (for example Sulfur based chemicals) there are two specific advantages of using Vitamin C in removing chlorine from water. The first is that Vitamin C does not lower the oxygen dissolved in water as much as sulfur-based chemicals. The second advantage is that Vitamin C is not toxic to other living cells including aquatic life at the levels used for de-chlorination.
What about the acidity of Ascorbic Acid?
Ascorbic acid is mildly acidic. In large enough doses it will lower the pH of the treated water. However at the levels used for de-chlorination, the impact of lowering the pH of water is not significant. The other from of Vitamin C which is Sodium Ascorbate is pH neutral and will not change the pH of the treated water.
How long the potency of Vitamin C will be active when used in Shower Filters?
Both Ascorbic Acid and Sodium Ascorbate forms of Vitamin C are generally stable compounds. In its dry form, the estimated shelf life is at least one year. But in shower filters, due to the constant flow of water the potency will be lost sooner as Vitamin C is used up to neutralize the chlorine. You can follow the replacement schedule recommended by the manufacturer.
How much water can Vitamin C Shower Filters neutralize?
One gram of Ascorbic acid will neutralize one milligram per liter of chlorine per 100 gallons of water. Approximately 2.5 parts of Ascorbic acid are required for neutralizing one part chlorine. Since Ascorbic acid is weakly acidic, the pH of the treated water may decrease slightly in low alkaline waters.
What is the chemical reaction of Vitamin C with Chlorine?
Ascorbic acid reacts with chlorine as shown below:
C5H5O5CH2OH + HOCL → C5H3O5CH2OH + HCl + H2O
Or in plain English:
Ascorbic acid + Hypochlorous acid → DehydroAscorbic acid + Hydrochloric acid + water
The reaction of Sodium Ascorbate with chlorine is shown below:
C5H5O5CH2ONa + HOCL → C5H3O5CH2OH + NaCl + H2O
Or in plain English:
Sodium Ascorbate + Hypochlorous acid → DehydroAscorbic acid + Sodium chloride + water